Apparatus for converting hydrocarbons



M r h 31,1959 1:. s. HALL HAL 2,880,078

APPARATUS FOR CONVERTING HYDROCARBONS Filed Dec. 28, 1953 3 Sheets-Sheet l FLUE GASES E r. PEBBLEN HEATER t I l1 [I6 HC'$+STEAM l2 F G- STEAM PEBBLE fsToRAcE REACTOR- |8 7 l4 REACTANT FLUID IN VEN TORS D. S. HALL L. Ev DEAN BY C. E. FORKEL 3 C. L. SEYER A 7' TORNEVS March 31, 1959 1:. sfHALL EI'AL 2,830,078

APPARATUS FOR CONVERTING HYDROCARBONS Filed. Dec 28, 1953 3Sheets-Sheet 2 SECOND PEBBLE BED INVENTORS. D s. HALL L. E. DEAN BY I c. E. FORKEL c. SEYER F/a.2 WWW/f v ATTORNEYS March 31, 1959 D. s. HALL m-AL 2,880,078

APPARATUS FOR CONVERTING HYDROCARBONS Filed Dec. 28, 1953 3 Sheets-Sheet 3 'INVEIVTORS D S. HALL L. E. DEAN C. E. FORKEL EYER ATTORNEYS United States Patent APPARATUS FUR CONVERTING HYDROCARBONS Dick S. Hall, Phillips, Tex., and LloydELDeamChester L. Seyer, and Curt E. F'orkel, Bartlesville, Okla assignors to Phillips Petroleum C0mpany,,a corporation of Delaware Application Decemberv 28, 1953,.SeriaLNo. 400,461

5 Claims. (Cl. 23-288) This invention relates to a process and apparatus for effecting contact between fluids and solid particulate contact material. In one (if-its more specificvaspects, it relates to an improved pebble heater reaction chamber.

'In another of its more specific aspects, it relates to an improved process for theconversion of hydrocarbons in a pebble heater reaction chamber wherein coke formation and deposition is reduced. In still another of its more specific aspects, it relates to a novel steam permeable expansion joint in the vapor-efiluent conduitrof a pebble heater reaction chamber.

Apparatus of the so-called pebble heater type has been utilized in recent years for the purpose of heating fluids to elevated temperatures. Such apparatus is especially suited for use in temperature ranges above those at which the best-available high-temperature alloys fail. Thus, such equipment can be used'ifor superheating steam or other gases and for the pyrolysis of hydrocarbons to produce valuable products,- suchas ethylene and acetylene, as welllas for other reactions and purposes. Conventional pebble-heater type apparatus includes two refractory-lined contacting chambers disposed one above the other and connected by a refractory-lined passageway or pebble throat off-"relativelyv narrow cross sections.

A principal'use of pebble heating apparatus is in the conversion of hydrocarbons, involving thermal or catalytic processes, such as cracking, hydrogenation, dehydrogenation, isomerization, polymerization, and the-like.

The term pebble, as used herein, refers'tothe small pebble-like solid particulate refractory elements comprising the contact mass mostgenerally used in" pebble heating apparatus. Pebbles so used are preferably substantially spherical and relatively uniform in size,-but in some instances they maybe rod shaped or irregular in size. Spheres of about /s" to l" in diameter function desirably, and those of about M4" to /2 aremost practical. Pebbles as used herein comprise any solid re fractory material of fiowable form, size, and strength,

suitable for carrying heat for transfer togases in contact therewith. Pebbles comprising beryllia, alumina, zirconia, mullite, and periclase, for example, make excellent contact material for most processes. Metal balls, such as nickel, Monel, Inconcl, iron, etc., have utility in specific processes. Pebbles and/or pebble surfaces may becatalytically active, or inert, to gases in contact therewith, depending on the specific process. For example, in non-catalytic cracking of a gas, the requisite is heat transfer and, therefore, an inert contact mass having a high heat-carrying capacity for transfer of heat to the gas in contact therewith is preferable. On the other hand, a catalytic gas conversion reaction would require the presence of a catalyst, in whichcase at least-the pebble surface area would comprise the specific catalytic material needed.

In the operation of pebble heater apparatus, .in many of the hydrocarbon-conversion processes, carbon. is: unavoidably formed and tendsto deposit and accumulate 2,880,078 Patented Mar. 31, 1959 high temperatures and then allowed to becooledto atmospheric temperatures. It isxat"once apparent'that the prevention of carbon deposits on the'i'nner surface of the pebble heater reactor chamber, so as to minimize shut-down periods, would result in a great savings, both in time and in expensiveequipment.

We have found that carbon deposits can be greatly discouraged and, in many instances, completely prevented by the injection of steam into the pebble heater reactor chamber so that the surface which normally 'is subject to an accumulation of carbon is contacted with reactant gases containing a predetermined amount of steam.

We have devised means for supplying steam in the proper amounts to those inner surfaces of the reactor which tend to accumulate a deposit of carbon.

Each of the following objects will be attained by 'at least one of the a spects of the invention.

An object of this invention is to provide a method for controlling the deposition of coke on the inner surfaces of a pebble heater reactor chamber.

It is another object to provide 'an' improved pebble heater reactor chamber.

It is still another object to provide a means for ex pansion and contraction of the vapor outlet conduitj'of a pebble reactor whereby the reactant vapors areconfined within the outlet conduit.

It is still another object to providea steam-permeable expansion joint in the vapor effluent conduit of apebble heater reactor chamber.

Other and further objects and advantages will be apparent to those skilled in the art upon study of the accompanying discussion and the drawing.

Broadly speaking, this invention comprises an improved pebble reactor chamber having a load-supporting dome located in the upper portion of the chamber equipped with pebble conduit passageways located around the periphery of the dome and means for introducing steam into the interior of the dome through openings around the periphery of the dome. The steam can'be supplied through the pebble conduit passageways or through openings around the periphery of the dome other than the pebble conduit passageways. The dome isco-nvex to the flow of pebbles and generally conforms to the angle of repose of the pebbles. The invention also comprises asteam-permeable expansion joint at the effiuent-vapor outlet whereby-vapors are prevented from leaking from the effluent conduit into the upper portion of the reactor chamber.

A better understanding of this invention will be obtained upon study of the accompanying drawing, wherein Figure 1 is a schematic illustration of heater apparatus.

Figure 2 is a sectional elevation of a preferred form of the pebble heater reactor chamber of this invention.

Figure 3 is'a sectional elevation of a modification-of the reactor chamber of this invention. 7

Figure 4 is a sectional elevation of another modification of the reactor chamber of this invention.

Referring now to Figure l of the drawing, the operathe pebble tion of the pebble heater apparatus will be described.

.turned through elevator 17 to pebble heater so as to complete the cycle. Make-up pebbles are maintained in pebble storage 18.

Referring to Figure 2, pebble heater reactor 13 comprises upright, elevated shell 21 closed at its upper and lower ends by closure members 22 and 23, respectively.

1 Pebble inlet conduit 12 is provided in the upper portion chamber 13, and steam inlet 24 is provided in the upper end of chamber 13. Load-supporting dome 25 is located in the upper portion of chamber 13 and is supported at its periphery by the refractory lining 26 of the chamber.

. A plurality of pebble conduits 27 are located around the periphery of dome 25, and a conduit 28 connects the interior of dome 25 to effluent conduit 29 located externally of the reactor chamber. A metal flange 31 connects the conduit 29 to the closed end 22 of the chamber. Flange 31 contains a ring 32 which extends a short distance into the closed end 22 of the chamber, and ring 32 has an inside diameter greater than the outside diameter of conduit 28 so that an annular space is provided between conduit 28 and ring 32. This annular space is packed with a compressible steam-permeable, refractory packing 33, for example, Fiberfrax (trademark). Fiberfrax (trademark) is fibrous aluminum silicate available from the Carborundum Company, Niagara Falls, New York. The annular space which results between conduit 28 and the refractory lining 26 of chamber 13 is also packed with this steam-permeable refractory packmg.

We have found that the compressible fiber packing can be conveniently installed by placing the material in position around the conduit and securing it in position by wrapping thereupon a layer of cardboard prior to installing the conduit in the reactor chamber. The packing permits expansion and contraction of the conduit and reduces the amount of steam required to prevent the escape of vapors from the vapor-eflluent line. A minor portion of the steam admitted to the reactor chamber through inlet 24 passes through the compressible packing at the expansion joint and is removed with the reactor effiuent. A second and major portion of the steam travels downwardly with the gravitating pebbles and passes through the pebble conduit passageways 'at the periphery of the dome 25 and then proceeds upwardly along the inner surface of dome 25 and is removed with the reactor effluent.

Referring now to Figure 3 of the drawing, the reaction chamber is modified by providing a supplemental supply of steam which is added adjacent the pebble conduit passageways in the periphery of dome 25. The steam is supplied through a manifold 35 and is admitted to the interior of dome 25 through inlets 36. Through the use of this modification of the invention, additional steam can be supplied to the interior of the dome at a temperature lower than that of the pebbles and of the dome.

Referring to Figure 4 of the drawing, reaction chamber 13 is modified by providing 'an additional supply of steam through a manifold 37 consisting of a steam line in the form of a helix embedded in the refractory material of dome 25. Steam inlets 38 are in communication with manifold 37 and the interior of dome 25. This modification provides a device whereby heat can be added to,

or removed from, dome 25 so as to provide greater flexibility in the operation of the reaction chamber.

We have found that by the injection of steam into the interior of the load-supporting dome in this reaction chamber, the deposition of carbon upon the inner surface of the dome can be substantially prevented and controlled. The steam inlets which admit steam into the interior of the dome are preferably adapted so as to direct the steam onto the inner surface of the dome. It is sometimes advantageous to have the steam inlets spaced so that substantially the entire inner surface of the dome can be subjected to a moving film of steam.

Although this invention has been particularly described in connection with conversion of hydrocarbon reactant materials, the device can be advantageously employed for the purpose of superheating steam or for the fixation of nitrogen or for conducting other reactions wherein large amounts of heat and high temperatures are required.

Variations and modifications are possible within the scope of the disclosure of the invention, the essence of which is the provision of an improved pebble heater'reaction chamber wherein steam is added to the interior of a load-supporting dome located in the upper portion of the reactor so as to prevent the deposition of carbon thereon and the provision of a steam permeable expansion joint in the vapor effluent outlet.

We claim:

1. An improved reactor chamber of pebble heater apparatus comprising an upright, elongated, refractory lined shell; refractory lined pebble inlet means in the upper end of said shell; refractory lined pebble outlet means in the lower end of said shell; fluid inlet means in the lower portion of said shell; fluid outlet means at the top of said shell; steam inlet means in the upper portion of said shell; a refractory dome, convex to the flow of pebbles and conforming to the angle of repose of said pebbles, located coaxially in said chamber above said fluid inlet means and below said pebble inlet means supported at its periphery by the chamber wall; a steam manifold imbedded within the structure of said dome; steam inlet means connected to said manifold; a plurality of steam pipe means connected to said manifold and projecting into the interior of the dome adjacent its periphery for supplying steam from said manifold to the zone within said dome in an amount sufficient to maintain a film of steam on the interior surface of said dome; a plurality of pebble conduit means at the periphery of said dome communicating between zones above and below said dome; a single fluid efiluent refractory conduit of substantially uniform cross sectional area extending vertically from the upper end of the zone within said dome into the fluid outlet means at the top of said shell; and steam permeable, compressible refractory packing located in the annulus formed between said fluid efliuent conduit and said fluid outlet means and between said fluid efiluent conduit and the refractory lining of said shell.

(2. An improved reaction chamber of pebble heater apparatus comprising a closed, upright, elongated, refractory lined shell; a single refractory lined pebble inlet means in the upper end of said shell; refractory lined pebble outlet means in the lower portion of said shell; refractory lined fluid inlet means in the lower portion of said shell; steam inlet means in the upper portion of said shell and spaced from said pebble inlet means; fluid outlet passageway through the refractory lining and chamber wall in substantially the center of the upper end of said refractory lined shell; a refractory dome, the upper surface of which is convex to the flow of pebbles and generally conforming to the angle of repose of pebbles, the lower surfare of which is a smooth, nonangular collector concave to the flow of gases, located coaxially in said chamber below said pebble inlet means and above said fluid inlet means and supported at its periphery by the chamber wall; a plurality of pebble conduit means at the periphery of said dome communicating between zones above and below said dome; a single fluid efiluent refractory conduit of substantially uniform cross sectional area extending vertically from the upper end of the zone within said dome into the fluid outlet passageway at the top of said shell; fluid withdrawal means connected to the fluid outlet passageway by a flange having an inside diameter greater than the outside diameter of said fluid efiiuent refractory conduit and extending partially through said refractory lined shell; and steam permeable, compressible, refractory packing material located in the annulus between said fluid effluent refractory conduit and said fluid outlet passageway and between said fluid eflluent refractory conduit and said flange.

3. The reaction chamber of claim 2 wherein the steam inlet means is a conduit in communication with the interior of the refractory lined shell above the refractory dome.

4. The reaction chamber of claim 2 wherein the steam inlet means is a plurality of conduits communicating with the interior of said refractory dome at its periphery.

5. An improved reaction chamber of pebble heater apparatus comprising a closed, upright, refractory lined, elongated shell; a single, refractory lined pebble inlet means in the upper end of said shell; refractory lined pebble outlet means in the lower portion of said shell; refractory lined fluid inlet means in the lower portion of said shell; a refractory dome, convex to the flow of pebbles and conforming generally to the angle of repose of pebbles, located coaxially in said reaction chamber below said pebble inlet and above said fluid inlet and supported at its periphery by the chamber wall so as to form a first pebble bed in the upper portion of said reaction chamber; a plurality of passageways located around the periphery of said dome so as to permit passage of pebbles to the zone below said dome to form a second pebble bed in the lower portion of said reaction chamber; steam inlet means in the upper portion of said shell and spaced from said pebble inlet means; fluid outlet means at the top of said shell; a single fluid efliuent refractory conduit of substantially uniform cross sectional area extending vertically from the upper end of the zone within said dome, through said dome and into the fluid outlet means at the top of said shell; and a steam permeable, compressible, refractory packing located in the annulus formed between said fluid eifluent refractory conduit and the refractory lining of said shell and between said fluid effluent refractory conduit and said fluid outlet means.

References Cited in the file of this patent UNITED STATES PATENTS 2,271,955 Russell Feb. 2, 1942 2,312,719 Kuhl Mar. 2, 1943 2,593,495 Shimp Apr. 22, 1952 2,623,842 Robinson Dec. 30, 1952 2,663,580 Shirk Dec. 22, 1953 2,673,791 McIntire Mar. 30, 1954 2,675,999 Bearer Apr. 20, 1954 2,677,602 Shirk May 4, 1954 2,703,936 Hut Mar. 15, 1955 2,719,818 Findlay Oct. 4, 1955 2,760,851 Gilmore Aug. 28, 1956 OTHER REFERENCES Yarway: Expansion Joints, Bulletin Ej 1906, pp. 2. 12 and 13. Yarway-Waring Co., Philadelphia, Pa. 

